Blower

ABSTRACT

A blower includes a motor, a fan, a casing, a control circuit, a roll pin, and a boss portion, and an end face of the boss portion at one side inserted to the shaft is provided with a groove having an opening and an bottom part to engaged with the roll pin, side walls of the groove are slanted to widen from a bottom part to the opening, the side walls have straight portions formed to confront each other in parallel to a longitudinal direction of the shaft and extending toward the opening from a start point corresponding to a central axis of the roll pin, and a distance between the confronting straight portions is equal to a diameter of the roll pin.

TECHNICAL FIELD The present invention relates to a blower. BACKGROUND ART

A blower in which a fan is detachable, a groove is formed in a fan boss, and the groove and a roll pin are engaged with each other to serve as a fan rotation stopper is known (for example, refer to PTL 1).

The blower will be described below with reference to FIG. 5 that is a perspective view showing a configuration of a conventional blower. As shown in FIG. 5, fan 101 includes boss portion 102 at the center thereof, and includes a plurality of blades 103 on the circumference thereof. At a center of axis of boss portion 102, shaft hole 105 in which shaft 104 (only the shaft is shown) of a motor is inserted and engagement groove 107 are formed, so that fan 101 is in a rotation stopping state. After shaft 104 is inserted into shaft hole 105, spinner 108 is rotated and fixed to a distal end side of boss portion 102 (fixing mechanism is not shown), and fan 101 is set in a retaining state. Engagement groove 107 mentioned here is a groove in a direction orthogonal to shaft hole 105, and is engaged with roll pin 106 mounted on shaft 104.

In the conventional blower as described above, roll pin 106 and engagement groove 107 collide with each other when a torque of the motor is changed or when the motor is activated to generate noise. As the countermeasure against the noise, a gap between roll pin 106 and engagement groove 107 may be reduced to prevent the collision. However, fan 101 is not easily mounted on shaft 104, and shaft 104 is disadvantageously imperfectly mounted on fan 101.

CITATION LIST Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 62-10532

SUMMARY OF THE INVENTION

A blower according to the present invention includes a motor, a fan driven by the motor, a casing that covers a circumference of the fan, a control circuit that drives and controls the motor, a cylindrical roll pin mounted on a shaft of the motor at right angle to an axis line of the shaft, and a boss portion inserted into the shaft, wherein an end face of the boss portion at one side inserted to the shaft is provided with a groove having an opening and a bottom part to engaged with the roll pin, side walls of the groove are slanted to widen from the bottom part to the opening, the side walls have straight portions formed to confront each other in parallel to a longitudinal direction of the shaft and extending toward the opening from a start point corresponding to a central axis of the roll pin, and a distance between the confronting straight portions is equal to a diameter of the roll pin.

With this configuration, since a width of an inlet port of the groove is larger than that of the roll pin when the roll pin is inserted into the groove, the roll pin can be easily inserted into the groove. When the roll pin is fixed to a position where the fan is rotated, since the width of the groove is equal to or smaller than the diameter of the roll pin, collision noise between the groove and the roll pin is prevented from being generated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a ceiling-embedded ventilation fan including a blower according to an embodiment of the present invention.

FIG. 2 is a diagram showing an interior of the ceiling-embedded ventilation fan including the blower.

FIG. 3 is a detail view of a portion A in FIG. 2.

FIG. 4 is a detail view of a portion B in FIG. 2.

FIG. 5 is a perspective view showing a configuration of a conventional blower.

DESCRIPTION OF EMBODIMENT

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Embodiment

FIG. 1 is an exploded perspective view of a ceiling-embedded ventilation fan including a blower according to an embodiment of the present invention, and FIG. 2 is a diagram showing an interior of the ceiling-embedded ventilation fan including the blower. The ceiling-embedded ventilation fan shown in FIGS. 1 and 2 is fitted in a roof space (not shown) of a room by being embedded in the roof space. The ceiling-embedded ventilation fan includes suction opening 1, frame 3, motor 4, fan 5, casing 6, dressed panel 7, control circuit 8, and circuit case 9.

Suction opening 1 mentioned here is arranged on a lower surface of the ceiling-embedded ventilation fan and corresponds to an opening of a ceiling board. Frame 3 configures a side surface of the ceiling-embedded ventilation fan and has discharge opening 2. Motor 4 is fixed to a top surface of frame 3. Fan 5 is driven by motor 4. Casing 6 covers the circumference of fan 5. Dressed panel 7 is detachably mounted to cover the opening in the lower surface of frame 3 from the room side. Control circuit 8 is mounted on the top surface of frame 3 to drive and control motor 4. Circuit case 9 stores control circuit 8 therein. Blower 23 mentioned here includes motor 4, fan 5, casing 6, control circuit 8, and circuit case 9.

FIG. 3 is a detail view of a portion A in FIG. 2, and FIG. 4 is a detail view of a portion B in FIG. 2. As shown in FIG. 3, blower 23 according to the embodiment of the present invention includes roll pin 13, groove 14, and boss portion 15. As shown in FIG. 4, blower 23 includes detaching device 22 including one pair of integrated holding units 11 and one pair of integrated pressing units 12.

As shown in FIG. 3, roll pin 13 has a cylindrical shape, and is mounted on shaft 10 of motor 4 at right angle to axis line 10 a of shaft 10. Boss portion 15 is arranged at the center of fan 5 and inserted into shaft 10. Groove 14 to engage roll pin 13 with motor-side end face 15 a that is an end face of shaft 10 on an insertion side is formed in boss portion 15. Groove 14 includes opening 18 and bottom portion 17.

As shown in FIG. 4, pressing units 12 are pressed to move holding portions 11. Shaft 10 is held by one pair of holding units 11. When pressing units 12 perform a nipping operation, a holding force of holding units 11 is released to make it possible to make fan 5 and shaft 10 detachable. A sensor-less DC motor is used as motor 4, and control circuit 8 is a drive circuit of the DC motor.

Since the sensor-less DC motor does not have a hall element in motor 4, a rotor position of motor 4 is fixed by a DC excitation mode in activation. Thereafter, the sensor-less DC motor outputs an energization signal of forced commutation and rotates. When the sensor-less DC motor rotates, induced voltages are generated from coils in phases (U phase, V phase, and W phase). When a signal showing the positive/negative of each phase terminal voltage including an induced voltage is input as a position signal, the energization signal of forced commutation is automatically switched to an energization signal based on a position signal input (induced voltage). For this reason, the sensor-less DC motor is driven by sensor-less driving. In the DC excitation mode, since shaft 10 rotates to the left and the right, collision repeatedly occurs between roll pin 13 and groove 14 to generate collision noise.

Since the sensor-less DC motor does not have a uniform rotating force and repeatedly generates uneven torque due to a cogging phenomenon, rotational movements of roll pin 13 and groove 14 do not coincide with each other. For this reason, collision repeatedly occurs between roll pin 13 and groove 14 to generate collision noise.

In contrast to this, as shown in FIG. 3, side wall 16 of groove 14 is slanted to widen from bottom portion 17 of groove 14 to opening 18. In a part of side wall 16, side wall 16 has straight portions 19 formed to confront each other in parallel to a longitudinal direction of shaft 10 and extending toward opening 18 from a start point corresponding to central axis 13 a of roll pin 13. More specifically, in FIG. 3, a part except for straight portions 19 of side wall 16 has a gradient extending in an upper left direction and having a small inclination. Distance 19 a between the confronting straight portions is equal to diameter 13 b of the roll pin.

As a result, when roll pin 13 is inserted into groove 14, since a width of an inlet port of groove 14 is larger than roll pin 13, fan 5 is easily inserted into shaft 10. When roll pin 13 is mounted at a fixing position, i.e., a position where fan 5 rotates, the width of groove 14 is equal to or smaller than diameter 13 b of the roll pin. For this reason, a gap is eliminated between roll pin 13 and groove 14, and collision noise is not generated.

Furthermore, as shown in FIG. 4, concave slot 20 with which holding units 11 are engaged is formed in shaft 10. A curved surface of shaft 10 in which concave slot 20 is formed is chamfered C-shaped surface 21. Diameter 21 a in a longitudinal direction of the shaft of the C-shaped surface is set to be equal to length 19 b of the straight portion shown in FIG. 3. As a result, when shaft 10 shown in FIG. 3 is inserted into fan 5, by a slipping force of holding units 11 along C-shaped surface 21 shown in FIG. 4, roll pin 13 is mounted at a position of straight portions 19.

As described above, in the blower according to the embodiment of the present invention, collision noise between roll pin 13 and groove 14 can be prevented from being generated, and fan 5 is easily fitted on shaft 10.

INDUSTRIAL APPLICABILITY

The present invention can be widely applied to a blower including a fan fitting device in which a roll pin is formed on a shaft of a motor used in a ventilation fan or the like, a groove engaged with the roll pin is formed as a fan rotation stopper in a boss portion of a fan.

REFERENCE MARKS IN THE DRAWINGS

1 suction opening

2 discharge opening

3 frame

4 motor

5 fan

6 casing

7 dressed panel

8 control circuit

9 circuit case

10 shaft

10 a axis line

10 b longitudinal direction

11 holding unit

12 pressing unit

13 roll pin

13 a central axis

13 b diameter of roll pin

14 groove

15 boss portion

15 a motor-side end face

16 side wall

17 bottom part

18 opening

19 straight portion

19 a distance between confronting straight portions

19 b length of straight portion

20 concave slot

21 C-shaped surface

21 a dimension of C-shaped surface in longitudinal direction of shaft

22 detaching device

23 blower 

1. A blower comprising: a motor; a fan driven by the motor; a casing that covers a circumference of the fan; a control circuit that drives and controls the motor; a cylindrical roll pin mounted on a shaft of the motor at right angle to an axis line of the shaft; and a boss portion inserted into the shaft, wherein an end face of the boss portion at one side inserted to the shaft is provided with a groove having an opening and a bottom part engaged with the roll pin, side walls of the groove are slanted to widen from the bottom part to the opening, the side walls have straight portions formed to confront each other in parallel to a longitudinal direction of the shaft and extending toward the opening from a start point corresponding to a central axis of the roll pin, and a distance between the confronting straight portions is equal to a diameter of the roll pin.
 2. The blower according to claim 1 further comprising one pair of integrated holding units that hold the shaft and one pair of integrated pressing units that are pressed to move the holding units, wherein the shaft has a concave slot engaged with the holding units, a curved surface of the shaft having the concave slot is a chamfered C-shaped surface, and a dimension of the C-shaped surface in a longitudinal direction of the shaft is equal to a length of the straight portion. 